[dev.ssa] cmd/compile/internal/ssa: make SETEQF and SETNEF clobber flags

They do an AND or an OR internally, so they clobber flags.

Fixes #12441

Change-Id: I6c843bd268496bc13fc7e3c561d76619e961e8ad
Reviewed-on: https://go-review.googlesource.com/14180Reviewed-by: Todd Neal <todd@tneal.org>

src/cmd/compile/internal/ssa/gen/AMD64Ops.go

@@ -112,7 +112,7 @@ func init() {
 		gp1flags  = regInfo{inputs: []regMask{gpsp}, outputs: flagsonly}
 		flagsgp   = regInfo{inputs: flagsonly, outputs: gponly}
 		readflags = regInfo{inputs: flagsonly, outputs: gponly}
-		flagsgpax = regInfo{inputs: flagsonly, clobbers: ax, outputs: []regMask{gp &^ ax}}
+		flagsgpax = regInfo{inputs: flagsonly, clobbers: ax | flags, outputs: []regMask{gp &^ ax}}
 
 		gpload    = regInfo{inputs: []regMask{gpspsb, 0}, outputs: gponly}
 		gploadidx = regInfo{inputs: []regMask{gpspsb, gpsp, 0}, outputs: gponly}

src/cmd/compile/internal/ssa/opGen.go

@@ -2502,7 +2502,7 @@ var opcodeTable = [...]opInfo{
 			inputs: []inputInfo{
 				{0, 8589934592}, // .FLAGS
 			},
-			clobbers: 1, // .AX
+			clobbers: 8589934593, // .AX .FLAGS
 			outputs: []regMask{
 				65518, // .CX .DX .BX .BP .SI .DI .R8 .R9 .R10 .R11 .R12 .R13 .R14 .R15
 			},
@@ -2515,7 +2515,7 @@ var opcodeTable = [...]opInfo{
 			inputs: []inputInfo{
 				{0, 8589934592}, // .FLAGS
 			},
-			clobbers: 1, // .AX
+			clobbers: 8589934593, // .AX .FLAGS
 			outputs: []regMask{
 				65518, // .CX .DX .BX .BP .SI .DI .R8 .R9 .R10 .R11 .R12 .R13 .R14 .R15
 			},